An I. S. machine includes a plurality (usually 6, 8, 10, or 12) of sections. Each section has a blank station including a mold opening and closing mechanism having opposed mold supports which carry blank mold halves. The mold supports are displaced by a suitable motor such as a pneumatic cylinder or profiled actuator (servo motor) between open and closed positions. A gob of molten glass will be delivered to the closed blank mold. The open top of the blank mold will then be closed by a baffle, which is displaced from a remote position to an advanced position by a suitable motor. The gob will be formed into a parison in the blank mold and after the surface of the parison is sufficiently cooled, the baffle will be retracted, the mold supports will be retracted and a pair of neck ring holder arms, which are rotatively supported by an invert mechanism, will be rotated 180 degrees to displace the parison to a blow station. The blow station also includes a mold opening and closing mechanism having opposed mold supports carrying blow mold halves. These mold supports are displaced between open and closed positions by a suitable motor. With the parison located at the blow station, the mold supports are closed, the neck ring arms are opened to release the parison, the invert mechanism returns the neck ring arms to the blank side and a blow head support, is displaced from a retracted position to an advanced position, where a supported blow head closes the blow mold. The parison is blown into a bottle and when sufficiently cooled, the blow head is retracted, the blank molds are opened and a takeout mechanism is displaced to pick up the formed bottle and carry it to a location above a dead plate where it is cooled while suspended and then deposited onto the dead plate. In addition to the movement of mechanisms and devices, process air to pneumatic cylinders or to mold cooling systems may also be controlled.
Each section is controlled by a computer which operates under the control of a 360 degree timing drum (programmable sequencer) which defines a finite number of angular increments around the drum at which mechanisms, etc., can be turned on and off each 360 degrees of rotation. Each valve is cycled (turned on and off) and each mechanism is cycled within the time of one machine cycle at operator selected “event angles”.
It is advantageous to operate an I.S. machine at the maximum possible cycle rate. The degree, to which this has been conventionally achieved, has been a function of the skill of the operator. Highly skilled operators have been able to run the same bottle, at a faster cycle rate than is possible with other operators.
To allow any company to operate the machine at a rate, that heretofore only the best operators could operate, a control for the IS machine was disclosed in U.S. Pat. Nos. 6,604,383, 6,604,384, 6,604,385, 6,604,386, 6,606,886, 6,705,119, 6,711,120, and 6,722,158. The teachings of these patents are incorporated herein by reference. In accordance with that control, a machine cycle is defined first by unwrapping the 360 event angle table into a constraint diagram. “Unwrapped” means the glass process cycle beginning with the formation of a gob of molten glass by severing the gob from a runner of molten glass and ending with the opening of the take out tongs when the formed bottle is located above the deadplate. This process cycle typically takes slightly more than two machine cycle periods. Then a mathematical representation of the unwrapped cycle constraint diagram is made that is capable of automated formulation and solution with the use of quadratic cost equations.
When an I.S. machine is controlled by servo controlled mechanisms, the limitation of interfering displacements or sequences between the glass and the mechanisms and between the mechanisms can be predicted with a fair degree of accuracy. In a conventional I.S. machine, which has mechanisms displaced with pneumatic motors, this predictability is far less accurate.